Almost as important as the aspects were the "Parts of Fortune"-the place in the heavens held by the Moon at the rising of the Sun.
"The most cautious of the astrologers, with some feeling of piety and the greatest veneration--assert with the most powerful reasons that the Moon prepared the substance, and the Sun created the form, that the former governed the night and the latter the day, that the one controlled the body and the other the mind."
Ptolemy thought that the Parts were observed both night and day. The Arabs, however, used only the nocturnal Part, and Apian is careful to warn men of this variation, "not for the purpose of proving the Arabs wrong, as I always respect them, but to leave the alternatives open to individual judgment."
The Parts of Fortune were the most important, but there were also Parts for every planet and they were computed for every conceivable purpose. There were the Parts of Life and Death, of Marriage and Brotherhood and the Benevolence of Brotherhood, of Enemies and Foreign Sojourn, and the Peace of Armies, of Birds, and the Nobility of the Baby and the Election of the King.
To read these subtle prophecies, astrologers divided the heavens into twelve stationary "houses" through which the wheel of stars and planets revolved. Six were above, and six below the horizon; and various Parts were assigned to various houses. Thus the part of marriage belongs to the seventh house, and is measured from Saturn to Venus for men, and from Venus to Saturn for women, all measurements being made. according to the order of signs.
Because of the supposed correlation between the heavens and the bodies of men, astrology played a tremendous part in all medicine of the period. A good doctor was forced to be an astronomer as Chaucer announced emphatically in the quotation which heads this chapter.
Apparently the procedure when a doctor was called went something like this. The doctor inquired what sort of a disease you had, if it was hot and dry or cold and wet, or some other combination of these "elements." Then he asked you for the precise moment when you first felt sick, as that was the hour of attack, for which the horoscope of the disease must be cast. He then went out and cast the horoscope, came back and told you what was going to happen.
Every sign was connected with some part of the body and might represent as many as four qualities. Each was dominated by a planet which gave it the name of its ruler. Of course the constellations had long since gone their precessional way, leaving the signs as purely artificial divisions, but this little discrepancy did not bother the astrologers at all. The sign of Aries was connected with the head, which was assigned to the first house of the heavens. It was dominated and ruled by Mars. The right ear was ruled by Saturn, the left by Mars. A man's right eye was governed by the Sun; his left eye by the Moon. For a woman it was the reverse. But Mars was the ruling planet for the whole of Aries. Saturn was the significator and ruler of melancholy, Jupiter of Blood, Mars and the Sun of bile, Venus and the Moon of phlegm and Mercury of blood and the spirit.
According to Ptolemy "any particular part of the body will not be injured by iron while the Moon is travelling through the sign which covers that part." That must have been a tremendous help to armored knights, if they had reliable calendars. When the Moon was in Aries, obviously, they would not need a helmet; but their necks would have to be covered as the Moon could only protect the neck while traveling through Taurus.
In this as in all astrology, the meaning was at first arbitrary; it might be a mere association of some legend with some god. The planets were named by the Babylonians, but the Greek and Roman myths assigned to the same divine being in much later times, were thought to have as much influence. Color too played an important part. If the ministrations of a certain planet were needed, an herb which bore the color of the planet was pulled and brewed according to explicit directions to serve as medicine for the poor sufferer. Then too it might be that at one time and another some symptom was noted with some peculiar heavenly aspect; and thenceforth it was written in the books that such an occurrence would mark a symptom.
Apian gives a prolonged list of diseases and their natural courses--and he adds an instrument for forecasting the dates when the crises will occur. Such records are not all absurd, though they could hardly be called scientific. The doctors had their own reputation to consider, and undoubtedly there was a spirit of humanity in their efforts of salvation. Certain diseases do follow certain courses. They had watched the patients as well as the heavens. But of course there were ridiculous mistakes as well.